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Abstract

Background: Genome-wide association studies (GWAS) are frequently used to nominate candidate genes for complex diseases, but are largely unable to identify the causative variant(s). One example: the AGTRAP-PLOD1 locus contains 6 genes in close proximity that are all associated with blood pressure (BP), making it difficult to delineate specific allele(s) that underlie human hypertension at this locus. Here we present a novel rat model that was developed to rapidly dissect GWAS loci using high-throughput gene mutation on a single hypertensive background.

METHODS: Agtrap, Mthfr, Clcn6, Nppa, Nppb, and Plod1 were individually mutated in the Dahl SS rat by zinc finger nuclease (ZFN) injections. ZFN-mutated and wild type (WT) control SS rats (n=8-25 per group) were assessed for BP and renal damage after 10 days on a 4% NaCl diet. Temporal gene expression during development of hypertension was assessed by qRT-PCR and confirmed by RNA-seq.

Conclusions: Combined with human GWAS, our data show for the first time that NPPA and CLCN6 are divergent mediators of BP at the AGTRAP-PLOD1 locus, while MTHFR mutation directly increases susceptibility to end-stage renal disease. These novel mechanistic data provide rationale for developing haplotype-specific therapies for treating hypertension.